Receiver-shield



J. P. MINTON.

RECEIVER SHIELD. APPLICATION FILED MAR, 27, 1918.

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Patented Nov. 15, 1921.

UNITED STATES PATENT OFFICE.

JOHN P. MINTON, OF EAST ORANGE, NEW JERSEY, ASSIGNOR TO WESTERN ELECTRICCOMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

RECEIVER-SHIELD.

Application filed March 27, 1918.

T 0 all whom it may concern Be it known that I, JOHN P. MINTON, acitizen of the United States, residing at East Orange, in the county ofEssex and State of New Jersey, have invented certain new and usefulImprovements in lReceiver- Shields, of which the following is a full.clear, concise, and exact description.

This invention relates to telephone re ceivers and more particularly toa means for shielding the receiver casing from the effects of extraneousnoises which would otherwise interfere with the satisfactory receivingof incoming messages.

In order to permit the accurate receiving of comparatively weakfluctuating voice currents, it becomes necessary in many cases to resortto the shielding of the telephone receiver to prevent the casing beingset in vibration by vibrations set up as a resultof the violentdisturbances occurring nearby, and also to prevent such vibrations fromreaching the ear directly. Such, for example, is the case in connectionwith the telephone apparatus used by aviators where the violentdisturbances set up by the exhaust cause the vibration of the casing ofthe ordinary type of head receiver and prevent satisfactory conversationunless the receivers are properly shielded.

It is therefore the object of this invention to provide an improvedmethod of shielding receivers to prevent interference by extraneousvibrations, and to accomplish this object a feature of the inventionresides in the employment of a shield of metal foil for the reflectionof sound waves originating outside of the-receiver casing. While thisfeature is shown in connection with a receiver support particularlysuitable for aviators helmets, the combination of this support with ahelmet forms no part of the present invention, being shown andspecifically claimed in a copending application of Fred D. Waldron,Serial No. 228,393, filed April 13, 1918.

This and other features of the invention are clearly shown in theaccompanying drawing in which Figure 1 is a plan view of a receiversupport embodying this invention; and Fig. 2 is a cross-sectional viewalong the line 22 of Fig. 1 showing in detail the construction of thesupport and the method by which it is attached to the aviators helmet-Specification of Letters Patent.

Patented Nov. 15,1921.

Serial No. 224,968.

Referring to the drawing, there is provided a cup-shaped member 5 formedof comparatively stiff leather, the outer edge 6 of which is formed tolie in a plane parallel to the central portion of the cup. The innerside of this cup is lined with a metal foil 7, lead foil approximatelyfive thousandths of an inch thick having been found to be very efficientfor this purpose. To afford mechanical protection to the metal foilthere is next provided a layer of heavy cloth or drilling 8. A ring 9 ofsoft felt is next provided, the inner diameter of this ring being sodimensioned as to allow the insertion of the receiver 10 which is of theordinary watch case type. The upper edge of the foil 7 is turned over,as shown at 11-11, and ring 12 of metal foil, preferably lead, completesthe metal shield about the receiver. Next to the ring 12 is placed aring 13 of stiff leather to afford mechanical protection to the metalfoil and also to add a certain amount of rigidity to the receiversupportand permit its being secured to the helmet. This support, asdescribechis now fastened into the aviators leather helmet of thewellknown type by stitching as shown at 14 through the leather of thehelmet 15-15, the edges 66 of the leather cup 5, the leather ring 13 andthe eiderdown helmet lining 16.

For the purpose of excluding all outside noises, there is provided anear-piece 17, preferably of :sponge rubber and having mounted therein aring 18 of soft gum rubber, which because of its greater rigidity,permits the ear-piece being secured as shown to the shouldered hardrubber cap 19 of the receiver 10. An aperture 20, in alinement with asimilar aperture in the receiver cap, permits the efiicient operation ofthe receiver. In the structure as described, the receiver casing isalmost entirely inclosed in the soft metal shield by means of whichsound waves coming from sources outside of the receiver are reflectedand thus prevented from setting the receiver casing in vibration. Thesoft felt packing serves as a further aid in absorbing whatever soundwaves pass through the metal-lining. In practice, it has been found thatreceivers shielded in the manner described may be used very efiicientlyfor aeroplane service, whereas receivers not protected by the leadshield are affected to such a degree by outside vibrations as to makeConversation very unsatisfactory.

lVhat is claimed is: V

1. In combination with a telephone receiver, means for preventingexternal vibrations from reaching the receiver casing, said meansincluding a shield of metal foil.

2. In combination with "a telephone receiver, means for preventingexternal vibrations from reaching the receiver casing, said meansincluding a shield of lead foil.

3. In combination with a telephone receiver, a pocket support for saidreceiver, and a metallic lining for said pocket support adapted toprevent external vibrations from reaching the receiver casing.

4. In combination with a telephone receiver, a pocket support for saidreceiver, a

lining of lead foil for said pocket support for causing the reflectionof external sound waves, and additional means within said support forcausing the absorption of external sound Waves.

A support for anacoustic device comprising a cup-shaped member in whichsaid device is removably positioned. a lining of metal foil for saidmember to shield the device from external vibrations. and additionalmeans inclosed within said lining for holding the device in position andcausing the absorption of external vibrations.

In witness whereof, I hereunto subscribe my name this 25th day of March,A. D. 1918.

JOHN P. MINTOX.

